Many chemical processes require a carefully controlled atmosphere or vacuum as a necessary condition. Semiconductor fabrication processes, for example, often require the absence of oxygen and water vapor in the growth chamber. As a specific example, the crystalline quality of silicon or silicon-germanium is limited by the presence of even small concentrations or partial pressures of oxygen and/or water vapor in the growth chamber. At temperatures of up to about 900.degree. C., where specialized semiconductor devices are prepared using current technology, the surface of silicon readily captures oxygen. Oxygen contamination of silicon surfaces, however, makes epitaxial growth very difficult and causes undesirable oxygen-related point defects in the semiconductor structure. Bulk float zone growth of silicon can also suffer from oxygen contamination, which can lead to defects and thermal donors that may cause undesirable effects. Therefore, a method is needed for effectively removing residual oxygen and water vapor from a semiconductor growth chamber without introducing other potentially contaminating materials.